The present invention relates to improvement of a monolithic semiconductor IC element (hereinafter called monolithic sensor IC), wherein the light-sensing element is provided on the same base plate.
Until now, in the case of the monolithic sensor IC as mentioned above, in many cases the light beam is also incident upon parts other than the light-sensing portion forming the light sensor. However, in case of such a monolithic sensor IC, electrons or positive holes are produced by means of the incidence of the light beam upon semiconductor parts other than the sensor or the p-n junction part so as to influence the output of the sensor, thereby causing problems because the noise index is substantially raised.
Further, in a case, for example, where the sensor output of the monolithic sensor IC is applied as a digital signal for effecting some control function, there is the possibility that erroneous operations could often occur if the noise component exceeds the noise margin of a digital circuit to which it may be applied.